mm/memblock.c:memblock_add_range(): if nr_new is 0 just return

If nr_new is 0 which means there's no region would be added, so just
return to the caller.

Signed-off-by: nimisolo <nimisolo@gmail.com>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memblock.c

@@ -584,6 +584,9 @@ int __init_memblock memblock_add_range(struct memblock_type *type,
 					       nid, flags);
 	}
 
+	if (!nr_new)
+		return 0;
+
 	/*
 	 * If this was the first round, resize array and repeat for actual
 	 * insertions; otherwise, merge and return.